1. Field of the Invention
The present invention relates generally to a method of performing a handover from a wideband code division multiple access system to a code division multiple access system and, more particularly, to a method of performing a handover by receiving a sync signal through the acquisition of a pilot signal from a code division multiple access network if it is determined that a handover to a code division multiple access system is necessary, requesting the handover from a wideband code division multiple access system using related information, and causing a mobile communication terminal to enter into a code division multiple access traffic mode based on a handover message from the system if the handover message responding to the request is received by the terminal from the system.
2. Description of the Related Art
A mobile communication terminal capable of being used both in a Code Division Multiple Access (CDMA) network and in a Wideband CDMA (WCDMA) network is referred to as a “multi-mode mobile communication terminal.” Such a multi-mode mobile communication terminal is equipped with both a Radio Frequency (RF) circuit and modem for a CDMA network and an RF circuit and modem for a WCDMA network so that the terminal can be used in both networks.
In case of switching from one base station to another base station during a call using a mobile communication terminal (i.e., a handover), it is preferable that the switching is performed without an interruption of the call. Conventionally, however, a handover from a WCDMA base station to a CDMA base station is performed by turning off the power of the WCDMA module and turning on the power of the CDMA module in the multi-mode mobile communication terminal. As a result, a call is disconnected when a mobile communication terminal moves from a WCDMA area to a CDMA area.